Approximately 15% of the U.S. population gets their drinking water from wells, cisterns and springs. As a result, over 45 million people do not have access to water that has been processed in a water treatment plant. This is not necessarily bad, as most groundwater in the U.S. is safe to drink;but there are still many cases where groundwater is contaminated and unfit or unhealthy to drink. Not only are dissolved metals a problem, but soluble anions such as perchlorate, nitrate and nitrite are hazardous at higher concentrations. Common contaminants in U.S. groundwater, both from natural and manmade sources, include significant quantities of magnesium and calcium chlorides (normal sources of hardness), heavy metals (e.g. lead), organic contaminants (e.g. pesticides), as well as trace amounts of hazardous materials such as arsenic, perchlorate, nitrates and nitrites. Currently, the majority of common household point-of-entry water purification systems mainly consist of a carbon filter and a water softener, both of which are not designed to remove dangerous ionic contaminants such as arsenate, perchlorate, nitrate, and lead. Carbon filters only remove suspended solids down to 0.5 5m while adsorbing some of the dissolved contaminants, mostly organics. Water softeners are designed to remove the metal cations (e.g., magnesium, calcium) that make water hard, and will not remove dissolved toxic anions. Thus, a point- of-entry well water purification system may be present in a household, but it is quite possible that dangerous ionic contaminants may still be present in the drinking water, even though it has been filtered and softened. To date, there is no small, point-of-use technology that will remove multiple ionic contaminants from well water in households where drinking water is supplied by a well. Technologies, such as ion exchange or reverse osmosis, exist to accomplish this task, but for single household use, these techniques often require large equipment, are too expensive to operate, and regular maintenance is an issue. When water purification beyond filtration and softening is needed due to groundwater contamination, a small, point-of-use water purification device that can be operated near a drinking water supply (i.e. kitchen sink) would be ideal for rural, single household use. TDA proposes to develop technology that will be incorporated into a point-of-use water purifier for removing problematic ionic contaminants from well water. Though operable in any household, the main application for TDA's water purification technology will be for use in rural homes where the main water supply is from a well or another potentially contaminated groundwater source. TDA's technology will be easy to use and more cost effective than current point-of-use water purification technologies. PUBLIC HEALTH RELEVANCE: Approximately 15% of the U.S. population gets their drinking water from wells, cisterns and springs, which have become increasingly contaminated over the years, making these groundwater sources unfit or unhealthy to drink without purification. To date, there is no small, cost effective point-of-use water purification technology that will remove multiple toxic, ionic contaminants from well water in single households where drinking water is supplied by a well. TDA proposes to develop a cost effective, easy to use technology that will be incorporated into a point-of- use water purifier for removing problematic toxic ionic contaminants from well water.